1. Field of the Invention
The invention relates to a continuous-casting apparatus, in particular for the continuous casting of steel, with a mould-supporting device and with a mould mounted so as to oscillate relative to the latter, the mould being supported on the mould-supporting device via guide elements extending approximately transversely to the direction of oscillation and absorbing forces in the elastic range, the guide elements being arranged approximately parallel to one another and, in the direction of oscillation, at a distance one above the other.
2. Related Art
A continuous-casting apparatus of this type is known from DE-A-2 248 066. In this continuous-casting apparatus, the mould is guided laterally via two spring assemblies arranged parallel to one another and one above the other and formed by band springs. Oscillation is brought about by a hydraulic cylinder which engages, on the one hand, on the supporting structure and, on the other hand, on a bracket of the mould. In this case, the two spring assemblies, which are arranged on one mould side in each case and are firmly clamped, on the one hand, to the supporting structure end, on the other hand, to the mould, have to absorb the guide forces, that is to say they are subjected to tensile or compressive load. On account of the compressive load, they have to be dimensioned to the buckling limit, thus resulting in a large thickness of the spring assemblies, specifically a far greater thickness than is necessary for the maximum tensile forces which occur.
In order, at the same time, to keep the bending stresses within the permissible range, it is necessary to dimension the spring assemblies with an appropriate length. Due to the large thickness of the spring assemblies, higher drive forces arise, that is to say the oscillation drive has to be made correspondingly more robust. Another disadvantage of this known design is that the life expectancy of the spring assemblies is reduced because of the high alternating bending stress occurring due to the large thickness, and, moreover, that, because of the large overall length of the spring assemblies, an increased amount of space is required in order to keep the alternating bending stress within a permissible scope. However, because of this, the accuracy with which the mould is guided is impaired, especially since the longer spring assemblies give rise to a more pronounced elastic behaviour, thus resulting, in turn, in greater deflections and deviations of the mould from the desired guide path. Furthermore, where longer spring assemblies are concerned, thermal influences become noticeable to an increased extent, specifically due to deviations of the mould from the desired guide path.
EP-A-150 357 discloses a billet guide for a continuous-casting mould, in which the mould is guided by means of a leaf spring which is clamped in a bridge-like manner at both ends in a spring carrier, the mould engaging on the leaf spring in the middle of the latter. Such a guide device makes it necessary to have a very large amount of space in the direction of the leaf-spring axis. Such a guide can therefore be provided only where there is sufficient space at the side of the mould. This is usually not the case where bloom or billet installations are concerned, and therefore this type of guide cannot be used for such installations.
The invention is aimed at avoiding these disadvantages and difficulties, and its set object is to provide a continuous-casting apparatus of the type described in the introduction, for which, in addition to a high degree of accuracy in the guidance of the mould, only a small amount of space is required and only low drive forces are needed for the oscillation drive. In particular, the space required is to be so small that it is possible in a simple way to use the continuous-casting apparatus for bloom and billet installation.
This object is achieved, according to the invention, in that at least one first guide element extends from the mould-supporting device towards the mould in a first direction and at least one second guide element extends from the mould-supporting device towards the mould in a direction opposite to the first direction.
According to a preferred embodiment, at least one supporting arm extending towards the mould-supporting device is provided on the mould and at least one supporting arm extending towards the mould is provided on the mould-supporting device, the said supporting arms being arranged approximately parallel to one another and, as seen in the direction of oscillation, so as approximately to overlap one another, and at least one guide element extends from the end region of one supporting arm towards the end region of the other supporting arm and is in each case fastened there itself.
For the non-tilt support of the mould, it is expedient to provide in each case at least two first guide elements and two second guide elements, in each case groups formed by a first and a second guide element being arranged at a distance from one another which is provided in the direction of oscillation. In this embodiment, the oscillation drive does not execute any guide forces. Should the mould be supported in a non-tilt manner via the oscillation drive, that is to say is prevented from tilting by the oscillation drive, for example is set in oscillation via eccentric drives, as described in EP-A-0 150 357, however, a single group formed by a first and a second guide element is sufficient.
For arcuate moulds, the continuous-casting apparatus is advantageously characterized in that a first guide element and a second guide element arranged approximately parallel to the latter are provided at an angle to a further first guide element and to the second guide element arranged approximately parallel thereto, for an arcuate mould the longitudinal axes of the guide elements advantageously being oriented approximately on radial lines of the arc defined by the arcuate mould.
The first and the second guide elements expediently form a structural unit in each case with a supporting arm 5. This embodiment allows a simple design and a simple installation of the guide elements or else a simple exchange of these. Moreover, the guide elements can be provided, in a particularly simple way in design terms, where they can be accommodated most easily with regard to space.
The guide elements are advantageously formed by spring bands, in particular in each case by spring-band assemblies, but it is also possible to use ropes, bars and/or diaphragms as guide elements.
The guide elements are expediently formed from steel or plastic, such as, for example, carbon fibre or glass fibre.